/*
  Copyright (c) 2011 Arduino.  All right reserved.
  Copyright (c) 2013 by Paul Stoffregen <paul@pjrc.com> (delayMicroseconds)

  This library is free software; you can redistribute it and/or
  modify it under the terms of the GNU Lesser General Public
  License as published by the Free Software Foundation; either
  version 2.1 of the License, or (at your option) any later version.

  This library is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
  See the GNU Lesser General Public License for more details.

  You should have received a copy of the GNU Lesser General Public
  License along with this library; if not, write to the Free Software
  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
*/

#ifndef __WIRING_TIME_H__
#define __WIRING_TIME_H__

#include "ch32v_def.h"
#include "core_debug.h"

#ifdef __cplusplus
extern "C"
{
#endif

  /**
 * \brief Returns the number of milliseconds since the Arduino board began running the current program.
 *
 * This number will overflow (go back to zero), after approximately 50 days.
 *
 * \return Number of milliseconds since the program started (uint32_t)
 */
  extern uint32_t millis(void);

  /**
 * \brief Returns the number of microseconds since the Arduino board began running the current program.
 *
 * This number will overflow (go back to zero), after approximately 70 minutes. On 16 MHz Arduino boards
 * (e.g. Duemilanove and Nano), this function has a resolution of four microseconds (i.e. the value returned is
 * always a multiple of four). On 8 MHz Arduino boards (e.g. the LilyPad), this function has a resolution
 * of eight microseconds.
 *
 * \note There are 1,000 microseconds in a millisecond and 1,000,000 microseconds in a second.
 */
  extern uint32_t micros(void);

  /**
 * \brief Pauses the program for the amount of time (in miliseconds) specified as parameter.
 * (There are 1000 milliseconds in a second.)
 *
 * \param ms the number of milliseconds to pause (uint32_t)
 */
  extern void delay(uint32_t ms);

  static inline void delayMicroseconds(uint32_t) __attribute__((always_inline, unused));

  static inline void delayMicroseconds(uint32_t us)
  {

  #if defined(CH32V3xx)
    
    __IO uint64_t currentTicks = SysTick->CNT;
    const uint64_t tickPerMs = SysTick->CMP + 1;

    const uint64_t nbTicks = ((us - ((us > 0)? 1: 0)) * tickPerMs) / 1000;

    uint64_t elapsedTicks = 0;
    __IO uint64_t oldTicks = currentTicks;

    do {
      currentTicks = SysTick->CNT;
      elapsedTicks += (oldTicks < currentTicks) ? currentTicks - oldTicks: ((tickPerMs + currentTicks) - oldTicks);
      oldTicks = currentTicks;
    } while( nbTicks > elapsedTicks);

  #else
    __IO uint32_t currentTicks = *((__IO uint32_t *)0xE000F004);
    const uint32_t tickPerMs = *((__IO uint32_t *)0xE000F00C) + 1;

    const uint32_t nbTicks = ((us - ((us > 0) ? 1 : 0)) * tickPerMs) / 1000;

  
    uint32_t elapsedTicks = 0;
    __IO uint32_t oldTicks = currentTicks;
      // core_debug(" c: %d t:%d n:%d \n", currentTicks, tickPerMs, nbTicks);
    do
    {
      currentTicks = *((__IO uint32_t *)0xE000F004);
      // elapsedTicks += (oldTicks < currentTicks) ? tickPerMs + oldTicks - currentTicks : oldTicks - currentTicks;
      elapsedTicks += (oldTicks < currentTicks) ? currentTicks - oldTicks: tickPerMs + currentTicks - oldTicks ;//  tickPerMs + oldTicks - currentTicks : oldTicks - currentTicks;
      oldTicks = currentTicks;
    } while (nbTicks > elapsedTicks);
  #endif
  }

#ifdef __cplusplus
}
#endif

#endif // __WIRING_TIME_H__